Heartless rogue Frank set on a different course (8)
I believe the answer is:
redirect
'set on a different course' is the definition.
'heartless rogue frank' is the wordplay.
'heartless' means to remove the middle letters.
'frank' becomes 'direct' ('direct' can be similar in meaning to 'frank').
'rogue' with its centre removed is 're'.
're'+'direct'='REDIRECT'
(Other definitions for redirect that I've seen before include "new tack" , "Aim a new way" , "Show the way again" , "Aim differently" , "Change course" .)